• Journal of Drive and Control
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• v.17 no.2
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• pp.55-62
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• 2020

There are two types of IMV for MCV, the spool type and the poppet type. The spool type is used in the existing excavator MCV and easily meets large-capacity flow conditions, but has a flow force problem which affects the spool control. The poppet type stably blocks the flow and has excellent rapid response. However, the larger the capacity, the larger the diameter of the poppet needed, requiring a strong spring to withstand the oil pressure. In this study, a bi-directional three-stage IMV for MCV that can be used in medium and large hydraulic excavators was proposed. This is a poppet type, enabling bi-directional flow control and resolves the problem of proportional solenoid suction force limitation. To investigate the validity of the proposed valve, the system was mathematically modeled and the static and dynamic characteristics were investigated through the simulation using commercial software. It has been concluded that the reverse flow is possible in a regeneration circuit and that the proposed IMV can be used to perform various excavation modes.

• Journal of Drive and Control
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• v.15 no.2
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• pp.46-51
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• 2018

Many research studies have been carried out related to saving energy and environmental pollution in the field of construction machinery. The best solution for reducing the related environmental pollution is to reduce fuel consumption by upgrading the energy efficiency of machinery used in this field. An efficiency upgrade in the field of construction machinery would mean minimizing the pressure loss in hydraulic pipe lines or achieving optimal operating conditions while responding to a load. One way to achieve this is to make an equivalent circuit, like an electrohydrostatic actuator, or to improve the spool type valve using the 4/3 way method. This study deals with an electrohydraulic proportional flow control valve. SimulationX software is used as a simulation tool for analyzing the dynamic characteristics. The analysis results, including the performance and characteristics of design parameters, are discussed and the validity of the theoretical analysis is also evaluated.

• Journal of Drive and Control
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• v.15 no.3
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• pp.49-56
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• 2018

Construction machinery is used to improve productivity in civil engineering work and construction work, and it is a lengthy operation, and consumes considerable fuel to cope with large loads. As a result, productivity and fuel consumption of the construction machine become the main deciding factors. In the hydraulic system of the excavator, the main control valve is the most critical position for control. The flow distribution for control performance is achieved by the metering orifice, that causes critical energy loss. To improve this, we propose a combination of a three port proportional pressure reducing valve and a poppet type flow control valve as an IMV to replace the existing spool type MCV. To validate the proposal, we analyze static characteristics by modeling mathematically, and analyze dynamic characteristics. Simulation using the AMESim software on the regeneration circuit of the boom cylinder up-down operation, verifies the energy-saving effect compared to the existing MCV when IMV is used.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.1
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• pp.19-25
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• 2011

This study presents the design of digital amplifier.controller for a proportional control valve and the development of PID discrete control scheme by using RCP(Rapid Controller Prototyping) system. RCP system is the device to embed the control code developed in PC into the microcontroller on-site. Ramp input test using the digital amplifier.controller developed in this study was carried out for the proportional control valve of domestic production and Bosch Rexroth respectively. The instability problem occurred around maximum displacement of localized valve spool at ramp input test was solved by supplementing offset current to the duty ratio of PWM(Pulse Width Modulation) driving signal to the solenoid. The comparison of test results between localized proportional control valve and Bosch Rexroth's product shows that the characteristics obtained by ramp input test and static flow gains are alike each other. Two valves are about the same in dead bands and hysteresis characteristics.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.74-80
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• 2006

This paper deals with the control and fault monitoring of a DDV hydraulic actuation system. A hydraulic servo system has a nonlinear dynamics of an orifice flow through a valve spool. A full nonlinear model for a DDV actuation system is driven, and linearized to a simple model which is convenient for a control loop and fault monitor design. A top level requirement on the performance and safety for the actuation system is introduced. A control system and fault monitoring structure which can meet these requirements are discussed. A simulation package for a DDV actuation system which has a triplex redundant structure is developed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.462-466
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• 1997

Proportional directional control valves (PDCVl adjust the amount of flow as well as flow direction in response to an electrical signal. This valves includes direct operated valves with or without spool position feedback. This paper investigates if it is possible to control pressure of fluids by means of the PDCV. A pressure signal is feed back to the Proportional-Integral (PI) controller, which is based upon a personal computer (PC). The PI control algorithm is implemented in a graphical programming language of LabVIEW. The results of experiments show the PDCV can be used a multi function valve of pressure control as well as direction control.

• Tribology and Lubricants
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• v.18 no.1
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• pp.68-74
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• 2002

In this study, the dynamic characteristics of the spool type counter balance valve are studied. The nonlinear governing differential eguations are derived. Routh-Hurwitz criterion is used to characterize the linearized eguations. Static and dynamic experiments are carried out for the determination of parameters that are necessary for the analysis and the stability of the system.

• International Journal of Safety
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• v.11 no.2
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• pp.10-14
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• 2012

Recently, the combined power plants are refocused rapidly as a replaceable energy system of the nuclear power plant. The large turbine is revolved highly at 1800~3600 rpm. Thus, the turbine speed should be monitored with mechanical and electrical method for a safety. The electrical cutoff valve which blocks the flow channel with the electrical signal is with a built in. The aim of this study is to develop a manufacturing technology through by the localization of a solenoid actuated directional control valve. Especially the results show performances of the solenoid valve by the experiments and modeling and the reliability estimation. Applied load port pressure was changed rapidly on the form of a quadratic curve over time. And in the cases of square waveform when 0~100 V and 20~120 V input voltage, it was driven on a stable state until 13.4 Hz and 16.6 Hz, respectively. We think that this study will give useful data for the electricity safety system of the combined power plant gas turbine.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.228-232
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• 2005

Automobiles are very important as modern society is developed. Increase of the number of the automobiles cause environmental problem, that is, air pollution. So, many countries are adopting a environmental law. Automobile manufacturing companies have developing methods to prevent air pollution with increase of the efficiency of automotive engines. PCV(Positive Crankcase Ventilation) system which is one of them is made by the closed loop that consists of combustion chamber, crankcase, manifold suction tube and manifold. PCV valve is attached on manifold tube to control the flowrate of blowby gas. PCV valve is an important part in this system but it is difficult to design PCV valve which satisfies the required flowrate of blowby gas. In this study, our purpose is to help a PCV valve designer with the development of a design program. We used 4th order Runge-Kutta method and Bernoulli's equation to analyze the spool dynamic motion. By the comparison between our program and experiment, we think that a PCV designer can use our program in their work place.

• Journal of Aerospace System Engineering
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• v.13 no.4
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• pp.50-59
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• 2019

The design of the main control valve, which is the main component of the flap control system, was based on actual manufacturing experience on the basis of trial and error method. In this paper, a model-based part design method is proosed. The flap control system consists of a main control valve, fail-safe valve, solenoid valve, LVDT and force motor. The main control valve consists mainly of a spool and slot. The important design parameters of the main control valve are the slot width, overlap and clearance. AMESim is linked to the model and it analyzes the flow path of the main control valve. Applying the proposed design procedure, it was confirmed that the required performance was satisfied within the allowable machining error range.